TW200303803A - Method to manufacture the rotor of a friction-vacuum-pump and the rotor manufactured by this method - Google Patents

Abstract

This invention relates to a method to manufacture a rotor (1) for a friction-vacuum-pump (21), which is constructed at least sectionally as turbo-molecular-vacuum-pump with rotor-blades (5) and stator-blades (9), where the rotor (1) has a hub (2), which supports on its surrounding-face the pump-structures; the pump-structures on the rotor-side are composed at least sectionally of blades (5) arranged in series (4), which are formed through the cutting operations from the surface of a slug; the production of the radial surrounding-grooves (3) belongs to the cutting operation, in the mounting state of the pump the stator-blades-series (9) are engaged in the surrounding-grooves (3); in order to simplify the operation of the rotor (1), it is suggested that other cutting operation is performed so that the outer-face of the slug is provided with one or several thread-grooves (13).

Description

200303803 (1) Description of the invention (The description of the invention shall state: the technical field to which the invention belongs, the prior art, the content, the embodiments, and the drawings). Method for manufacturing rotor of vacuum pump. The present invention also relates to a rotor made by this method. It is known in the prior art to make the individual wings of the rotor of a turbomolecular vacuum pump by the following method: the outer surface of a cylindrical blank (preferably composed of aluminum) must be provided with a radial circumference The grooves and the axially aligned grooves form blades, and each blade is located in the plane perpendicular to the rotation axis. In order to obtain blades that can be pumped, each blade must overlap. Each blade usually has a different clearance angle / overlap angle depending on the distance from the entrance. Other deformations of the blade profile are not allowed by conventional manufacturing methods. In addition, it is known to process the blade by milling the surface of the blank, and then the overlapping process is unnecessary at this time. This process requires a long processing time. What is particularly sought is that the blades of different blade series have different flanking profiles and / or clearance angles. SUMMARY OF THE INVENTION The object of the present invention is to reduce the currently required processing time, and thus reduce the manufacturing cost of the rotor of a friction vacuum pump. The above-mentioned object in the present invention is achieved by the features of the scope of patent application. The present invention allows a series of impellers to be formed by cutting operations in a simple manner with different clearance angles or wing profiles. This is achieved by the formula 200303803: the slope of the thread groove changes in accordance with the desired situation. With the method of the invention, the milling time can be reduced to a minimum or the milling process can be completely replaced by a rotary operation. Embodiments Other advantages and details of the present invention are described below with reference to the embodiments in Figs. 1 to 8. In these drawings, the rotor is represented by 1 and its hub is represented by 2. In the manufactured rotor, the hub 2 carries the respective blade series 4 through at least one section of the circumferential groove 3, wherein each of the blades is represented by 5. In the installed state (Figures 7 and 8), each stator blade series 9 is held in the circumferential groove 3. Rotation of the rotor 1 causes gas to be supplied from the suction side 1 1 to the pressure side 12 of the rotor 1 as desired. From Figures 1 to 3, it can be seen how the rotor 1 of the present invention is made. First, a cylindrical blank is provided with threaded grooves 13 (picture 1) or radial circumferential grooves 3 (picture 2). After this step, the hub 2 of each rotor 1 is formed. The hub 2 in FIG. 1 carries one or more threaded ribs 14 and the hub 2 in FIG. 2 carries radial aids 15 each extending through the periphery. The rotor 1 in FIG. 1 is provided with a circumferential groove 3, and the rotor 1 in FIG. 2 is provided with a thread groove 13. In these two ways, the rotor 1 of Fig. 3 is thus formed. A series of blades 4 separated by a circumferential groove 3 remains on the hub 2. The profile (width, length, cross section) and clearance angle of the blade 5 of the blade series 4 are related to the width and depth of the adjacent grooves 3, 13 and are related to the thread grooves in the height of the respective blade series 4. The slope of 13 is related. The rotor 1 in FIG. 4 has threaded grooves in the entire height of the rotor 1-1, 3 200303803, and a radial circumferential groove 3 is additionally provided only in an upper region thereof. By this measure, a single-piece rotor 1 for a friction vacuum pump can be formed, which is composed of a turbo molecular pump in a segmented manner (suction side) and a molecular pump (hollow pump) on the pressure side. Finally, it can be identified from Figure 4 that the inclination (mainly the inclination change) of the threaded ribs 14 can be arbitrarily selected, so that the conveying characteristics can be accurately adjusted according to the pressure existing at each position of the conveying channel. Figures 5, 6, and 7 show a rotor 1 in which the threaded ribs 14 have a fixed slope over their entire height. The rotor 1 in FIG. 5 is in a semi-finished state; it has only threaded ribs 14 or threaded grooves 13. Figures 6 and 7 show different views of the completed rotor 1 (Figure 6 is a side view and Figure 7 is a view tilted from below). After the threaded grooves 13 are formed, a radial circumferential groove 3 is formed by rotation. FIG. 8 is a sectional view of a pump driving area of the turbo molecular pump 21. The stator blade 9 is grasped in a radial circumferential groove 3 of the rotor 1 made according to the present invention. Cylindrical stators 22 having a stator ring and a blade ring are used to support the stator blades 9 in a conventional manner. The depth of the circumferential groove 3 gradually decreases from the suction side 11 to the pressure side 12. The same applies to the blade length of blade series 9 which is pumped. The result is a conveying cross-section that gradually becomes smaller from the suction side to the pressure side. The method of the present invention allows a rotor 1 to be manufactured in a simple manner, which has the above or other conveying characteristics. In the embodiment shown in Fig. 9, only the section on the suction side of the pump 21 is constituted by a turbo molecular pump. The pressure side section is composed of thread grooves / -ribs 1 3, 1 4 and its depth / height decreases toward the pressure side. It forms a hollow pump together with the inner surface of the stator 22. There is also a third pump stage 2 3 which is connected to the hollow pump stage of the rotor 1 200303803. The hollow pump stage surrounds a thread 2 4 which enters the stator 2 2 and forms a hollow pump stage with a cylinder 25 fixed to the rotor 1. BRIEF DESCRIPTION OF THE DRAWINGS The rotors of the present invention are shown in Figures 1 to 4, where the rotors in Figures 1 and 2 are in a semi-finished state. Figures 5 to 7 are detailed illustrations of the rotor of the present invention, wherein the rotor of Figure 5 is in a semi-finished state. Figures 8 and 9 Sectional views of the frictional vacuum pump and rotor of the present invention

Illustration. Description of the main parts of the symbol 1 rotor 2 hub 3 circumferential groove 4 blade series 5 blade 9 stator blade series 12 13, 14 15 2 1 2 2 2 3 2 4 2 5 suction side pressure side radial rib radial rib pump stator pump stage Threaded cylinder

Claims (1)

200303803 Patent collection and application 1. A method for manufacturing a single-piece rotor (1) for a friction vacuum pump (2 1), which comprises at least a section of a rotor blade (5) and a stator blade (9) Turbo molecular vacuum pump, the rotor (1) has a hub (2), which carries various pump structures on its circumferential surface; the pump structure on the rotor side consists of a series of (4) blades (5) arranged at least in sections. Each blade is formed by the surface of the blank through the operation of cutting processing; the manufacture of radial circumferential grooves (3) belongs to the operation of cutting processing. Holding in the radial circumferential groove (3), it is characterized in that another cutting operation is to provide one or more thread grooves (1 3) on the outer surface of the blank. 2. The manufacturing method according to item 1 of the patent application scope, wherein the threaded structure is first made by milling and then rotated to make each circumferential groove (3). 3. The manufacturing method according to item 1 of the scope of patent application, wherein the thread structure and the circumferential groove (3) are made by rotation. 4. The manufacturing method according to item 1 of the patent application scope, wherein the circumferential groove (3) is first made and then the threaded structure is made. 5. A rotor (1) made by the manufacturing method according to any one of claims 1 to 4, which is characterized in that: a screw groove (1 3) and a circumferential groove (3) form a rotor blade ( 5). 6. The rotor (5) according to item 5 of the scope of patent application, wherein the rotor (5) has thread grooves (1 3) and segmented circumferential grooves (3) over its entire height. 7. If the rotor (1) of the item 5 or 6 of the scope of patent application, the depth of each slot (3, 1 3) is from the suction side end (1 1) of the rotor (1) to the pressure side end (1 2) to -10- 200303803 gradually becomes smaller in a section manner. 8. The rotor (1) as claimed in claim 5, 6, or 7, wherein the rotor (1) carries a coaxially arranged cylinder (25) on its pressure side end (12).